In processes heretofore in use for producing semiconductor devices such as ICs and LSIs, microfabrication by lithography using a resist composition is being conducted. Recently, with progress in the degree of integration in integrated circuits, formation of ultrafine patterns in the submicron or quarter-micron region has come to be required. With this trend, the exposure light wavelengths also tend to become shorter, i.e., the exposure light is shifting from g-line to i-line and further to KrF excimer laser light. Currently, lithographic techniques employing electron beams, X-rays, or EUV ray besides excimer laser lights are being developed.
In particular, electron-beam lithography is regarded as a next-generation or next-to-next-generation technology for pattern formation, and there is a desire for a resist having high sensitivity and high resolution.
From the standpoint of sensitivity enhancement, chemical amplification type resists mainly utilizing an acid-catalyzed reaction are used as resists suitable for such electron-beam or X-ray lithographic processes.
Various investigations have hitherto been made in order to improve the performance of chemical amplification type resists. Especially from the standpoint of acid generators, the following investigations have been made. For example, patent document 1 (Japanese Patent No. 2,968,055) discloses a trifluoromethanesulfonate compound having a phenolic hydroxy group, patent document 2 (JP-A-2001-142200) discloses a specific benzenesulfonate compound having a phenolic hydroxy group, and patent document 3 (JP-A-10-39500) discloses a polyvalent arylsulfonium compound.
However, none of these techniques of the related art simultaneously satisfies beam shape reproducibility, resolution, and line-and-space pattern profile rectangularity. Beam shape reproducibility is an important property for forming a desired pattern shape. In particular, the ability to reproduce the pattern shape of bent parts in drawing a bent line pattern is important from the standpoint of later processing (ultramicrofabrication of the substrate).
[Patent Document 1]                Japanese Patent No. 2,968,055        
[Patent Document 2]                JP-A-2001-142200        
[Patent Document 3]                JP-A-10-39500        